Endodontic management considerations for Type III dens invaginatus based on anatomical characteristics: A case series

Dens invaginatus (DI) is a developmental anomaly of the teeth characterised by the in-folding of the enamel into the dentin. Oehlers' Type III DI is the most serious form, in which the inherently invaginated channels communicate with periodontal and dental pulp tissue, increasing the risk of bacterial contamination. However, varying and complex anatomical features make diagnosis and treatment challenging. Conventional endodontic therapies promote healing by avoiding unnecessary interventions (e.g., surgical or other invasive treatments). Radiographic examination can reveal the structural details of such malformations. We obtained multiple procedural details for treating Type III DI based on radiographic analyses from our clinical experience. In addition, we introduce a new classification strategy for the management of Type III DI that is more applicable to treatment needs. This study aimed to discuss the anatomical features and current treatment considerations of Type III DI.

A Novel Diagnostic and Treatment Approach to an Unusual Case of Dens Invaginatus in a Mandibular Lateral Incisor Using CBCT and 3D Printing Technology

BACKGROUND

This case report demonstrates the use of three-dimensional (3D) models produced from a cone beam computed tomographic (CBCT) volume to develop a treatment strategy for a rare type of dens invaginatus (DI) in a mandibular incisor.

METHODS

A patient with DI Type IIIa presented for endodontic treatment. Following CBCT evaluation, the complex morphologic nature of the invagination required additional diagnostic tools for treatment planning. The fabrication of 3D models provided clarity regarding the treatment strategy. Treatment involved intracanal medication with calcium hydroxide Ca(OH)2, nonsurgical root canal therapy (NS-RCT) of the main canal, and endodontic surgery for the DI anomaly using mineral trioxide aggregate (MTA), bone graft, and platelet-rich fibrin (PRF) membrane.

RESULTS

The use of 3D models provided an invaluable guide for proper treatment. Complicating factors were diagnosed and planned for accordingly.

CONCLUSIONS

It is difficult to appreciate the anatomical complexity, the extent, and the nature of the invagination of rare Type III DI morphology. CBCT imaging and 3D models played a critical role in the pre-treatment planning to ensure a predictable outcome. A 3D model is recommended as a diagnostic tool in treating complex cases where the DI morphology is wide, oblique, or the foraminal opening is irregular.

Treatment opinions for dens invaginatus: A case series

Dens invaginatus (DI) is a rare congenital dental malformation characterized by enamel or cementum folded into dentine. Such teeth are susceptible to caries, pulp infection or necrosis and periradicular lesion. The complex anatomy of this disease results in difficult treatment and a high rate of therapeutic failure. Therapeutic options, such as debriding and filling invagination, root canal treatment (RCT) and intentional replantation, vary according to the morphology and infection of the involved tooth. The present study reports five cases of DI with chronic apical periodontitis. The treatment strategies and procedures, including RCT, removing the invagination, intentional replantation and surgical treatment, are discussed according to the classification and the condition of pulp and periapical tissue. The study also reports the prognosis: All patients were followed up for ≥12 months and all teeth demonstrated periapical healing and clinical asymptomatic. In summary, appropriate treatment is based on accurate analysis of the anatomical variation in different types of DI and intentional replantation is a reliable and viable treatment to preserve the tooth.

Non-surgical and guided-bone-regeneration surgical management of Type-3b dens invaginatus with an apico-marginal defect: A case report

BACKGROUND

Dens invaginatus (DI), an unusual developmental anomaly is a challenge for the operating dentist with regard to its diagnosis and treatment. This case report presents the successful management of a Type-3b DI in a permanent maxillary lateral incisor associated with a large radicular cyst and communicating apico-marginal defect (Von Arx type IIb).

METHODS AND RESULTS

A 19-year-old female patient reported pain and palatal swelling. During the clinical examination, tooth #12 exhibited tenderness to percussion, and presented a deep periodontal pocket depth (PPD) of 12 mm, along with grade I mobility. Radiographic examination revealed a large peri-radicular radiolucency with atypical tooth morphology. Cone beam computed tomography clarified the complicated root canal anatomy to be Type-3b DI associated with an apico-marginal defect. The case was managed successfully by non-surgical endodontic therapy followed by surgical intervention utilizing a guided bone regenerative (GBR) approach. Eighteen-month follow-up showed an asymptomatic and functional tooth with a significant reduction in pocket depth. The periapical radiographs showed continued healing of the osseous defect.

CONCLUSIONS

The successful healing outcome of a challenging case, characterized by a complex DI morphology, a large peri-radicular lesion, a through-and-through defect, and a combined endodontic-periodontal apico-marginal defect was achieved through accurate diagnosis, treatment planning, and execution using contemporary endodontic and periodontal treatment techniques. The application of GBR techniques during the surgical phase of treatment may have contributed to the improved regenerative healing outcome in this case, which was initially considered prognostically questionable.

KEY POINTS

Why is this case new information? Type-3b DI exhibits a complex root canal structure, each case displaying unique characteristics, necessitating a case-specific treatment plan. In this case report the Type-3b DI morphology was associated with a large peri-radicular, through and through defect and combined endodontic periodontal apico-marginal defect. The treatment approach involved incorporating guided bone regenerative (GBR) principles during the surgical phase. This case report contributes to the existing evidence on the diagnosis and successful management of Type-3b DI with a concurrent apico-marginal defect. What are the keys to successful management of this case? The successful management of a prognostically challenging case was achieved through a closely integrated multidisciplinary coordination between the endodontist and periodontist. Utilization of contemporary techniques and tools contributed to the successful management The use of three-dimensional radiological examination through cone beam computed tomography enabled a precise preoperative assessment, facilitating the formulation of a treatment plan for managing both the Type-3b DI morphology and the associated peri-radicular lesion. Employing GBR techniques in peri-radicular surgery may have assisted in the healing of through-and-through periapical defects with concurrent apico-marginal defects (Von Arx type IIb). What are the primary limitations to the success of this case? A complex root canal anatomy associated with Type-3b DI morphology A large peri-radicular through and through defect with concurrent apico-marginal defect. Difficulty in weekly and long-term follow-up of the patient.

Long-term follow-up of single-visit pulp revascularisation for the dens evaginatus and dens invaginatus: Cases report

This article documents cases of single-visit pulp revascularisation for dens evaginatus and dens invaginatus, without using intracranial medicaments or antibiotics, aiming to provide a potentially applicable protocol for pulp revascularisation procedure in a single-visit. Two patients with chief complaints of pain and swelling visited a dental hospital. Radiographs revealed that the causative teeth had an open apex and periapical radiolucency, and the teeth were diagnosed as pulp necrosis and acute apical abscess or symptomatic apical periodontitis. For both cases, single-visit revascularisation was completed without intracanal medicaments or antibiotics. The patients were periodically recalled to evaluate periapical healing after treatment. The apical lesion healed, and the root dentin thickening was observed. The single-visit pulp revascularisation procedure without using specific intracanal medicaments can produce clinically favourable results for these dental anomalies.

Endodontic management of type IIIb dens invaginatus in central incisor: A case report

We described a type IIIb dens invaginatus, its root canal treatment, and results on 3- and 12-month visits. Despite its significant challenges, proper endodontic therapy in such cases can cause positive prognosis and successful outcome.

Root Maturation of an Immature Dens Invaginatus Despite Unsuccessful Revitalization Procedure: A Case Report and Recommendations for Educational Purposes

BACKGROUND

The clinical management of teeth with complex dens invaginatus (DI) malformations and apical periodontitis may be challenging due to the lack of routine. The aim of this case report is to describe the endodontic treatment of an immature tooth with DI and to discuss strategies for preclinical training for teeth with such malformations.

CASE REPORT

A 9-year-old male presented with an immature maxillary incisor with DI (Oehlers Type II) and apical periodontitis which was diagnosed by cone beam computed tomography (CBCT). Revitalization was initially attempted but then abandoned after failure to generate a stable blood clot. Nevertheless, considerable increase in both root length and thickness could be detected after medication with calcium hydroxide followed by root canal filling with MTA as an apical plug.

CONCLUSIONS

The endodontic management of teeth with DI requires thorough treatment planning. In immature teeth, under certain conditions, root maturation may occur even with conventional apexification procedures. From an educational perspective, different strategies including CBCT and 3D-printed transparent tooth models for visualization of the complex internal morphology and redesigned 3D-printed replica with various degrees of difficulty for endodontic training, can be used to overcome the challenges associated with endodontic treatment of such teeth.

Rare variant of dens invaginatus with accessory root and labial talon cusp in maxillary lateral incisor-Case report

Dens invaginatus (DI) often causes dysmorphic changes in both the crown and root. This case report presents a complicated type 3a DI in a maxillary lateral incisor with labial talon cusp and root bifurcation. Although lingual talon cusp is common in maxillary lateral incisor, labial talon cusp is rare. An auxiliary palatal root in maxillary lateral incisor is also unusual. No such case involving all three variations has been described in the literature. The DI was classified as type B4 according to Schulze and Brand, as it involved division of pulp and root. DI was managed by orthograde MTA, radisectomy and periodontal regeneration was done for the palatal root. Labial talon associated with DI and can lead to early periodontal/pulpal involvement. Type 3 DI can affect the root with marked dilatation and division. Additional palatal root should be carefully detected in type 3a DI and managed with the aid of CBCT.

Retrospective Study of Intentional Replantation for Type Ⅲb Dens Invaginatus with Periapical Lesions

INTRODUCTION

In recent years intentional replantation (IR) has received more attention for its high tooth survival rate and wide range of indications. Type Ⅲb dens invaginatus (DI) is one of the most serious types of tooth malformation and is very challenging to treat. When root-end surgery is not feasible, IR may be considered as an alternative to extraction. However, there is little information available on the use of IR for type Ⅲb DI. Therefore, this study investigated the treatment outcomes and clinical procedures used for treatment of type IIIb DI with IR.

METHODS

IR was performed to treat 10 patients with type Ⅲb DI with periapical lesions. Each tooth was examined clinically and radiologically. IR was selected by these patients as their treatment plan after treatment procedures were discussed. An experienced endodontist and an experienced surgeon performed all treatments using the same protocol and surgical technique. Postoperative assessments were comprised of clinical and radiographic examinations, tooth survival and functional status.

RESULTS

The follow-up period ranged from 4 to 39 months. After IR, eight teeth were functioning properly with no clinical and radiological signs of pathology. The other two teeth had complications after IR comprising recurrence of periapical radiolucency and sinus tract formation in one patient, and development of a mucosal fenestration in another. Both of these patients received additional surgery and showed marked improvements.

CONCLUSION

Our study evaluated the most clinical data to date and showed that IR may be a reliable alternative for type IIIb DI with a periapical lesion.

Prevalence of dens invaginatus and palatogingival groove in North India: A cone-beam computed tomography-based study

Aim

The aim of this study was to study the prevalence of dens invaginatus (DI) and palatogingival groove (PGG) in maxillary lateral incisors, and the occurrence of apical periodontitis in association with these anomalies in North Indian population.

Methodology

Maxillary lateral incisors in 163 cone-beam computed tomography scans were assessed to determine the presence of DI and PGG. Anomalies identified were then classified as per Oehler's and Gu's classification, respectively. Their side and gender predilection and association with apical and lateral radiolucency was also studied.

Statistical Analysis

Descriptive data were reported as percentages. Chi-square analysis was used to determine the association with gender and side predilection.

Results

DI was present in 13.5% of the scans, while PGG was present in 7.3% of the scans. No significant gender and side predilection was observed. 6.67% of lateral incisors with DI and 25% of lateral incisors with PGG had an associated apical radiolucency. 33.33% of lateral incisors with PGG had an associated lateral radiolucency.

Conclusions

There is a high prevalence of DI and PGG in maxillary lateral incisors.

Dilated Odontoma Arising in the Mandibular Third Molar Germ: Report of a Case of an Unusual Lesion in an Uncommon Site

Dilated odontoma is the most severe variant of dens invaginatus. It is extremely uncommon in the posterior mandible. It is thought to originate during the morpho-differentiation stage of dental development. However, its etiology and pathogenesis remain obscure. We report here the clinical and pathologic findings of an incidentally discovered dilated odontoma arising in the left third mandibular molar germ of an 11-year-old male and a review of the pertinent literature. As dilated odontoma is not established as an independent entity in the current WHO classification of odontogenic tumors and is the result of a well-established developmental anomaly of the tooth (that is, the invagination of the enamel organ into the dental papilla), it should be better identified as dilated dens invaginatus.

Activated Epithelial FGF8 Signaling Induces Fused Supernumerary Incisors

FGF8, which is specifically expressed in the dental epithelium prior to the E12.5 bud stage, is a key player during odontogenesis, being responsible for the initiation of tooth development. Here, to investigate the impact of persistent FGF8 signaling on tooth development, we forcibly activated FGF8 signaling in the dental epithelium after the bud stage by generating K14-Cre;R26R-Fg8 mice. We found that a unique type of fused supernumerary incisors is formed, although morphologically resembling the features of type II dens invaginatus in humans. Further analysis revealed that ectopically activated epithelial FGF8 alters the cell fate of the incisor lingual outer enamel epithelium, endowing it with odontogenic potential by the activation of several key tooth genes, including Pitx2, Sox2, Lef-1, p38, and Erk1/2, and induces de novo formation of an extra incisor crown lingually in parallel to the original one, leading to the formation of an extra incisor crown and fused with the original incisor eventually. Meanwhile, the overdosed epithelial FGF8 signaling dramatically downregulates the expression of mesenchymal Bmp4, leading to severely impaired enamel mineralization. Based on the location of the extra incisors, we propose that they are likely to be rescued replacement teeth. Our results further demonstrate the essential role of FGF8 signaling for tooth initiation and the establishment of progenitor cells of dental epithelial stem cells during development.

Multiple dens invaginatus in Wilson's disease: A case report

Wilson's disease (WD) is a rare autosomal recessive genetic disease that affects copper metabolism. Anomalies can be seen in the dento-maxillofacial structures of WD patients. Dens invaginatus (DI) is an uncommon tooth anomaly, and its incidence in decidious and permanent molars is even lower. This case report primarily explored the multiple DI of a patient with WD. A 9-year-old boy was admitted to our clinic with complaints of pain and swelling in the right lower molar area. It was learnt that the patient was diagnosed with WD after he was born. Fistula, submandibular lymphadenopathy and diffuse swelling were detected. Using cone-beam computed tomography (CBCT), multiple DIs were observed in bilateral bimaxillary four first molars and deciduous molars. When the patient's systemic condition was considered, extraction was planned under oral antibiotic therapy and was performed. During the 6-month follow-up, uneventful healing was observed.

Investigation of dens invaginatus in a Chinese subpopulation using Cone-beam computed tomography

OBJECTIVE

This study assesses the prevalence and characteristics of dens invaginatus (DI) in a sample of Chinese population by using cone-beam computed tomography (CBCT) images.

METHODOLOGY

A retrospective study was conducted by using the CBCT images of 1,004 patients. The whole dentition was evaluated for the presence and characteristics of DI. Periapical pathosis status and bilateral feature of affected teeth were also examined.

RESULTS

Dens invaginatus was observed in 85 of 1,004 subjects, with a prevalence of 8.47% and a tooth prevalence of 0.494%. Males presented a higher prevalence of DI than females (p = .011). Type I DI was the most commonly observed type of dens invaginatus, followed by type II and type III. The structure form of different types of DI was various. Overall 2.48% of the patients with type I DI, 5.88% of the patients with type II DI, 100% of the patients with type III DI had apical pathosis. Bilateral DI was found in 63.53% of the affected patients.

CONCLUSIONS

This study indicates that DI was not rare, and clinicians should be aware of its existence. CBCT examination can provide an accurate representation of dental anatomy and should be incorporated into early diagnosis and treatment planning for teeth with DI.

Mandibular Carnassial Tooth Malformations in 6 Dogs-Micro-Computed Tomography and Histology Findings

Objective: To document the clinical, radiographic, and histological characteristics of mandibular first molar teeth with developmental abnormalities previously attributed to dens invaginatus and enamel pearls in dogs. Materials and Methods: Affected mandibular first molar teeth from dogs were evaluated grossly and via intraoral radiography. Endodontically and/or periodontally compromised teeth were extracted and subjected to some combination of micro-computed tomography, histopathology, and immunohistochemistry with anti-amelogenin antibody. Results: Six dogs with developmental abnormalities of mandibular first molar teeth were identified, representing 11 affected teeth. The condition was bilateral in 5 dogs, while in 1 dog, only one mandibular first molar tooth was present. Patient weight ranged from 1.7 to 6 kg (median = 4.09 kg). On intraoral radiographs, root convergence or parallelism was noted in 6 of 11 teeth, and root dilaceration was noted in 3 of 11 teeth. Eight teeth required extraction due to periapical lucencies or periodontitis. On micro-CT, the abnormal teeth were characterized by the presence of abnormal, heterogenous hard tissue with beam attenuation characteristics midway between that of enamel and dentin. Enamel fissures were identified in 4 of 8 teeth, while ectopic radicular enamel was identified in 2 of 8 teeth. The abnormal tissue was traversed by channels measuring 20-40 μm in diameter. Channels communicated with the enamel fissures in 2/8 teeth, the furcation in 2/8 teeth and the pulp in 4/8 teeth. The abnormal tissue was frequently surrounded by disorganized dentin. Histologic features of enamel and dentin were absent from the abnormal tissue and immunohistochemistry to detect amelogenin in the abnormal tissue was negative in all samples. Conclusion: The dental abnormalities described here correspond to a previously unrecognized developmental abnormality involving the mandibular first molar teeth in dogs. The developmental origin of the abnormal tissue could not be ascertained, and further investigations are required to determine the mode of formation, origin of the abnormal tissue, and factors associated with development. These developmental abnormalities more closely resemble molar-incisor malformation, rather than dens invaginatus or enamel pearls as described in humans. The authors propose that affected mandibular first molar teeth simply be referred to as having carnassial tooth malformations.

Missense Pathogenic variants in KIF4A Affect Dental Morphogenesis Resulting in X-linked Taurodontism, Microdontia and Dens-Invaginatus

The etiology of dental anomalies is multifactorial; and genetic and environmental factors that affect the dental lamina have been implicated. We investigated two families of European ancestry in which males were affected by taurodontism, microdontia and dens invaginatus. In both families, males were related to each other via unaffected females. A linkage analysis was conducted in a New Zealand family, followed by exome sequencing and focused analysis of the X-chromosome. In a US family, exome sequencing of the X-chromosome was followed by Sanger sequencing to conduct segregation analyses. We identified two independent missense variants in KIF4A that segregate in affected males and female carriers. The variant in a New Zealand family (p.Asp371His) predicts the substitution of a residue in the motor domain of the protein while the one in a US family (p.Arg771Lys) predicts the substitution of a residue in the domain that interacts with Protein Regulator of Cytokinesis 1 (PRC1). We demonstrated that the gene is expressed in the developing tooth bud during development, and that the p.Arg771Lys variant influences cell migration in an in vitro assay. These data implicate missense variations in KIF4A in a pathogenic mechanism that causes taurodontism, microdontia and dens invaginatus phenotypes.

[Apical barrier technology to treat chronic apical periodontitis caused by type Ⅱ dens invaginatus: a case report]

Dens invaginatusis a rare malformation of the teeth, resulting in frequent pulp necrosis and chronic apical periodontitis. In this paper, the apical barrier technology was used to treat a case of chronic apical periodontitis caused by type Ⅱ dens invaginatus.

[Endodontic-periodontal combined therapy for type Ⅲ dens invaginatus in maxillary lateral incisor: a case report]

We report a clinical case of type Ⅲ dens invaginatus with endodontic-periodontal lesion in a maxillary lateral incisor. The palatal radicular anomaly predisposed the tooth to periodontal lesions. The caries along the palatal groove caused tooth pulp necrosis and periapical lesions. By means of microscopic root canal therapy, apical surgery, and guided periodontal tissue regeneration, the apical and periodontal infection were controlled, and the affected tooth was retained.

Combined endodontic therapy and peri-radicular regenerative surgery in the treatment of dens invaginatus type III associated with apicomarginal defect

Dens invaginatus (DI) is a dental developmental abnormality, probably resulting from an infolding of the dental papilla during tooth development. The following case report presents a case of Type III DI with apicomarginal defect and peri-radicular lesion, diagnosed with cone-beam computed tomography scan and treated with combined orthograde endodontic therapy and peri-radicular regenerative surgery. Follow-up examination at 2 years revealed uneventful healing and improvement in the status of the tooth-supporting structures.

Surgical management of lateral incisor with type II dens invaginatus and a periapical pathosis: A case report with 1-year follow-up

Dens invaginatus is a relatively common dental malformation resulting from an infolding of enamel organ into the dental papilla varying in depth into the tooth tissues. Complex morphological anatomy associated with the pulpal pathology presents inaccessibility to completely remove the necrotic pulp tissues and hence poses challenges in rendering endodontic treatment. A combination of nonsurgical and surgical management in treating such cases is advisable depending on the presented variations. The present case reports the surgical endodontic treatment of an immature maxillary lateral incisor with type II dens invaginatus and periapical pathology.

Management of Dens Invaginatus Type II Associated with Immature Apex and Large Periradicular Lesion Using Platelet-rich Fibrin and Biodentine

Dens invaginatus (DI) poses peculiar challenges in endodontic treatment of teeth because of distortion of pulpal space. A case of Oehlers type II DI with open apex and large periapical lesion is reported. The case was managed using cone-beam computed tomography (CBCT), operating microscope, platelet-rich fibrin (PRF), and Biodentine. A 15-year-old male patient presented with palatal swelling. Pulp sensibility testing of right maxillary lateral incisor was negative. Intraoral periapical digital radiograph revealed an Oehlers type II DI with open apex and periapical radiolucency. A CBCT scan was performed to study the anatomy, determine the true extent of the periapical lesion, and form a treatment plan. A diagnosis of Oehlers type II DI with pulp necrosis and acute periapical abscess was made. Two-visit endodontic treatment was performed. In the first visit, the invaginated central mass was removed under operating microscope, chemo-mechanical preparation was done, and double antibiotic paste dressing was placed. In the second visit, the canal was sealed with apical matrices of PRF and Biodentine as filling material. The patient was asymptomatic and radiographs revealed continued healing of the osseous defect at follow-up visits. A CBCT scan at 30 months showed complete continuity of periodontal ligament space, healing of labial and palatal cortical plates, and formation of intercortical bone. The advances in endodontic armamentarium and technology, like CBCT and operating microscope, have made successful treatment of challenging cases possible. PRF and Biodentine as apical matrices and filling material, respectively, proved to be effective in the present case.

Successful orthograde treatment of dens invaginatus Type 3 with a main C-shaped canal based on cone-beam computed tomography evaluation

Dens invaginatus is a rare anatomic variation that is found primarily in maxillary lateral incisors. The management of dens invaginatus is challenging for clinicians; diagnosing the type of malformation, choosing the most appropriate treatment, and carrying out treatment are complicated by the intricate root system of these teeth. The following case report describes the diagnosis and treatment planning of dens invaginatus Type 3 after cone-beam computed tomography evaluation.

Endodontic management of dens invaginatus Type IIIb: Case series

Dens invaginatus may be seen as a developmental malformation. It is characterized by an invagination of the enamel and dentin, creating a lumen inside the affected tooth, which may extend as deep as the apical foramen. Oehlers Type IIIb is considered the most challenging clinical conditions. The purpose of this study is to discuss the nonsurgical endodontic management of vital and necrotic dens invaginatus Type IIIb cases. Due to the complex anatomical consideration of dens invaginatus Type IIIb, endodontic treatment is extremely technique sensitive. A conservative approach was used in a vital case to treat the invaginated lumen only, to preserve the vitality of the pulp, and a more invasive approach was used in a necrotic case to debride the lumen and necrotic pulp for proper disinfection of the root canal system. Although different, all the approaches were successful. The clinical signs and symptoms were resolved. The vital case remains vital after 19 months, and the recall radiographs were able to show satisfactory periapical healing both in vital and necrotic cases. Due to the highly complex anatomy of dens invaginatus Type IIIb, the decision of preserving the pulp vitality may not be related only to pulpal diagnosis but also to the technical requirements of the treatment. Although very technically sensitive, it may be possible to treat the invaginated lumen exclusively, while preserving the vitality of the pulp. Necrotic cases may require a more aggressive approach to achieve a favorable prognosis.

Preaxial polydactyly associated with a MSX1 mutation and report of two novel mutations

We report two novel heterozygous missense MSX1 mutations in two Thai families (c.739C>T; p.Pro247Ser and c.607G>A; p.Ala203Thr). The p.Ala203Thr mutation was found in a female patient, her sister, and their father and is associated with unilateral cleft lip and palate, hypodontia, and microdontia. The p.Pro247Ser mutation was found in a three-generation Thai family and was associated with bilateral cleft lip and palate, hypodontia, microdontia, and dens invaginatus. The proband also had preaxial polydactyly of the left hand. The role of Msx1 in limb development in mice is discussed. Intrafamilial variability of the phenotypes is clearly evident. This is the first time that a limb anomaly has been reported to be associated with a mutation in MSX1.

A retrospective comparative study of cone-beam computed tomography versus rendered panoramic images in identifying the presence, types, and characteristics of dens invaginatus in a Turkish population

INTRODUCTION

This study assessed the presence, characteristics, and type of dens invaginatus (DI) by using cone-beam computed tomography (CBCT) and panoramic images rendered from CBCT images. In addition, the findings of the imaging techniques were compared.

METHODS

We evaluated 300 CBCT images to determine the type of DI, the presence of an impacted tooth near the DI, and the presence of apical pathosis. The McNemar test was used to compare the prevalence of DI according to CBCT and panoramic images rendered from CBCT images.

RESULTS

The presence of DI was lower on panoramic images rendered from CBCT images (3% of the patients) compared with on CBCT images (10.7% of the patients) (P < .001). According to the CBCT images, the distribution of teeth with DI was as follows: maxillary lateral incisors (75%), maxillary central incisors (6.8%), mandibular premolars (4.6%), mesiodens (9%), maxillary canines (2.3%), and mandibular canines (2.3%). Type I DI was the most commonly observed type of invaginatus (65.9%), followed by type II (29.5%) and type III (4.6%). All patients with type III DI and 25% of the patients with type II DI had apical pathosis at the time of referral, but periapical lesions were not observed in teeth with type I DI. In total, 13.6% of DI cases had impacted teeth.

CONCLUSIONS

CBCT can be recommended as an effective diagnostic device for identifying DI because it provides an accurate representation of the external and internal dental anatomy.

Talon cusps occurring concurrently with dens invaginatus on a permanent maxillary lateral incisor: a case report and literature review

A talon cusp is a prominent accessory horn-like structure that projects from the cingulum or cementoenamel junction of the maxillary or mandibular teeth. It can occur in primary and permanent dentition and can lead to occlusal interference, irritation of the tongue, pulpal necrosis, caries, and periodontal problems. Talon cusp has been reported to affect both sexes, and may be unilateral or bilateral. Talon cusps occur most often on the palatal surface of permanent maxillary incisors. A comprehensive literature review revealed only 6 reported cases of facial talon cusps. A talon cusp occurring simultaneously with dens invaginatus in a tooth is extremely rare; to date, only 9 case reports have been published. This article presents a unique case of concurrent dens invaginatus and palatal and facial talon cusps in the right maxillary central incisor of a 12-year-old girl.

Dens invagination: A review of literature and report of two cases

Dens invaginatus occurs as a result of the invagination of the enamel organ. These cases may present difficulties with respect to its diagnosis and treatment because of canal morphology. It frequently leads to caries, pulpal, and periodontal involvement with necrosis and loss of attachment. The knowledge of classification and anatomical variations of teeth with dens invaginatus are of great importance for correct treatment. This article presents two case reports of two different types of dens invaginatus along with profound review of the literature regarding etiology, epidemiology, and histology. It discusses clinical appearance and diagnosis, and it provides guidelines for decision-making and treatment of invaginated teeth.

Diagnosis and management of a maxillary lateral incisor exhibiting dens invaginatus and dens evaginatus

This case report, involving an indigenous Australian, presents the diagnosis and non-surgical endodontic management of a 22 with developmental abnormalities. They include a dens evaginatus and a dens invaginatus that extends to an apical burst in a second truncated root. Cone-beam computed tomography and endodontic microscopy were not available to the clinician. This case report focuses on ambiguities appearing in the literature relating to classification and terminology associated with the abovementioned developmental anomalies. It also demonstrates the need to methodically collect and cautiously interpret available information before initiating endodontic intervention. Axial inclination, distance perception, internal demarcation and spatial awareness, together with an understanding of dental anatomy, embryology and histology and associated physiology and pathology, allowed the clinician to accurately predict the point, the angle and the depth of coronal access. Sensibility of the dentino-pulpal complex was maintained. Critical thinking, experience, innovation, problem-solving and established principles can compensate for inaccessible technologies.

WNT10A mutations also associated with agenesis of the maxillary permanent canines, a separate entity

Agenesis or isolated hypodontia of the maxillary permanent canines is a very rare dental anomaly. We report on nine unrelated Thai patients with this condition. Three of them had one affected parent. Three heterozygous missense mutations (p.Arg171Cys; p.Gly213Ser; and IVS2+1G>A) were identified in WNT10A in six patients. The p.Gly213Cys mutation was found in four patients. One of the patients who had p.Gly213Ser mutation also had peg-shaped (microdontia of the) maxillary lateral incisors with dens invaginatus. The mothers of two patients who carried the same mutation as their affected sons (p.Gly213Ser and p.Arg171Cys) had microdontia of the maxillary permanent lateral incisor. Our study has demonstrated for the first time that agenesis of the maxillary permanent canines is a distinct entity, associated with mutations in WNT10A. Inheritance appears to be autosomal dominant. Agenesis of the maxillary permanent canines may accompany by microdontia of the maxillary permanent lateral incisors and dens invaginatus of the maxillary permanent lateral incisors. Mutations could not be identified in the coding exons of WNT10A in three patients. They might be located outside the coding exons, including the promoter regions. However, it is likely that agenesis of the maxillary permanent canines is a heterogeneous disorder.

Dens invaginatus (Type III B)

Dens invaginatus or 'dens in dente' is a developmental malformation of the tooth resulting from infolding of the dental papilla before calcification. This article presents a case of dens invaginatus occurring in maxillary right lateral incisor of a 45-year-old male patient. The patient presented with pain and clinically missing maxillary right canine. The tooth was found to be non-vital. Radiographic examination revealed the tooth-in-tooth appearance of lateral incisor with a dilated pulp chamber. The crown of impacted canine was found within the pulp chamber of lateral incisor. Owing to this unique clinical presentation, both the lateral incisor and the impacted canine were extracted. Histopathologic examination confirmed the diagnosis of Dens invaginatus Type III B. A brief review on etiopathogenesis, radiographic features and treatment of dens invaginatus has also been included.

Nonsurgical endodontic treatment of type II dens invaginatus

The endodontic treatment of teeth with dens invaginatus, characterized by an infolding of enamel and dentin, extending deep into the pulp cavity near the root apex, may be complicated and challenging. The complexity of the internal anatomy may create challenges for the complete removal of diseased pulpal tissue and the subsequent sealing of the canal system. Because of the bizarre root canal anatomy and widely open apex, a combination of nonsurgical and surgical endodontic treatment or extraction is the most common choice of therapy. This article describes case reports of nonsurgical endodontic treatment of Type II dens invaginatus associated with periradicular lesion.